Derivatives of 1,2-dihydro-2-oxo-4-aminopyrimido(4,5-b)quinoxaline-5,10-microndioxides

ABSTRACT

1,2-DIHYDRO-2-PXO-4-AMINOPYRIMIDO 4,5-B!QUINOXZLINE5,10-DIOXIDES DEMONSTRATE ANTIMICROBIAL ACTIVITY AN CAN BE USED AS SUCH OR IN COMPOSITIONS FOR COMBATTING INFECTIONS AND IN IMPROVING FEED EFFECIENCY. THE COMPOUNDS, OF WHICH 1,2-DIHYDRO-2-OXO-4-DIMETHYLAMINOPYRIMIDO 4,5-B! QUINOXZLINE-5,10-DIOXIDE IS A TYPICAL EMBODIMENT, ARE PREPARED FROM THE APPROPRIATE 3-AMINOQUINOXALINE-1,4DIOXIDE-2-AMIDINE AND PHOSGENE OR AN ALKYL CHLOROFORMATE FOLLOWED BY TREATMENT WITH BASE.

line-5,10-dioxide of the formula:

United States Patent Claims priority, application Germany, May 7, 1971,

P 21 22 571.8 Int. Cl. C07d 51/46 US. Cl. 260-247.2 A 10 Claims ABSTRACT OF THE DISCLOSURE The present invention pertains to 1,2-dihydro-2-oxo-4- 'aminopyrimido[4,5-b]quinoxaline-5,10-dioxides, to methods for the preparation and use of these compounds, and

to compositions adapted to the utilization of their antimicrobial properties. In particular, this invention is directed' at a compound selected from the group consisting of a 1,2-dihydro-2-oxo-4-aminopyrimido[4,5-b]quinoxawherein each of R and R independent of the other is lower alkyl or (lower alk0xy)lower alkyl or R and R or straight hydrocarbon chain containing from 1 to 18 ,carbon atoms. Representative of such alkyl groups are thus methyl, ethyl, propyl, isopropyl, butyl, isobutyl, ,sec.butyl, tert.butyl, pentyl, isopentyl, neopentyl, tert. pentyl, hexyl, isohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, and the like.

The term lower alkyl denotes a univalent saturated branched or straight hydrocarbon chain containing from 1 to -6 carbon atoms. Representative of such lower alkyl groups are thus methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec.butyl, tert.butyl, pentyl, isopentyl, neopentyl, tert.pentyl, hexyl, and the like.

The term lower alkoxy denotes a straight or branched hydrocarbon chain bound to the remainder of the molecule through an ethereal oxygen atom as, for example,

methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy,

pentoxy and hexoxy.

As indicated, the present invention also pertains to the physiologically acceptable non-toxic acid addition salts V M of these basic compounds. Such salts include those derived 3,814,756 Patented June 4, 1974 ice from organic and inorganic acids such as, without limitation, hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, methane sulphonic acid, acetic acid tartaric acid, lactic acid, succinic acid, citric acid, malic acid, maleic acid, sorbic acid, aconitic acid, salicylic acid phthalic acid, embonic acid, enanthic acid, and the like.

The present invention also pertains to the novel process utilized in the preparation of the compounds of Formula I. In particular, the 1,2-dihydro-2-oxo-4-aminopyrimido [4,5-b]quinoxalines of Formula I are obtained through treatment of an amidine of the formula:

wherein R and R are as herein defined with phosgene or lower alkyl chloroformate and treating the product thereby formed with an organic or inorganic base.

The initial reaction between the amidines of the Formula II and the alkyl chloroformate or phosgene is carried out at temperatures of between about 20C. and about 100 0., preferably about 60 C. to about C., at normal or elevated pressure, generally normal pressure. At least about 1 mol of phosgene or alkyl chloroformate is employed per mol of amidine and preferably 1 to 10 mols of phosgene or 1 to 2 mols of alkyl chloroformate. Suitable diluents for the reaction include all inert organic solvents, preferably non-polar ones such as, for example, aliphatic and aromatic hydrocarbons, such as petrol, benzene and toluene, and halogenated hydrocarbons, such as chlorobenzene or dichlorobenzene.

The amidine of Formula II or its salt, preferably its hydrohalide, especially its hydrochloride, is thus suspended in a diluent and either phosgene is introduced into the suspension, or chloroformate acid alkyl ester is added, An intermediate product, which can be if desired isolated, is thus formed which can be diagrammatically depicted as follows:

in which R and R are as defined above. Under the action of an organic or inorganic base, the intermediate of Formula IH is converted into the compound of Formula I. The intermediate of Formula 111 can be either isolated as for example by filtration, before being reacted with a base, or reacted directly with a base without. isolation. Suitable organic bases include primary, secondary and V tertiary amines, such as aliphatic, cycloaliphatic, aromatic,

iso-propanol, n-, isoandterL- butanol' and about 1' mol ofthe base is then added.

If the intermediate is treated with base without isolation, it is advisable to first remove any excess phosgene which may still be'present in the reaction mixture. This .cantbe accomplished for examplesimply by warming or aeration. The mixture is then treated with water or a polar organic solvent, preferably about the same amount of water as organic solvent and about 1 mol of the base is added per mol of the amidine originally employed.

In either case, the treatment of the intermediate with the base is carried out at temperatures of from about .l C. to about 50 C., preferably 20'' C. to 30 C.

mirabilis, Proteus morganii and Proteus rettgeri; Klebsiella as for example Klebsiella pneumoniae; Salmonelleae; Pseudomonodaceae as for example Pseudomonas -aeruginosa; Cocci, especially Staphylococci, such as for example Staphylococcus aureus; Streptococci as for example Streptococcus pyogenes; Enterococci as for example Streptococcus faecalis; and M ycoplasma as for example Mycoplasma pneumoniae and Mycoplasma hominis. As a result of this activity and their low toxicity, the compounds are useful in human and veterinary medicine in the treatment of infections in animals caused by Gram positive and Gram negative bacteria and by mycoplasm'a. Infections of the respiratory tracts in poultry, especially in chicks, and mastitis of cows can be mentioned as particu larly responsive to such treatment.

The method of treatment of microbial infections in animals according to this invention comprises the administration to the animal of an antimicrobially effective amount of a l,Z-dihydro-2-oxo-4-aminopyrimido[4,5-b] quinoxaline of Formula I, or a salt thereof. The amount administered will of course depend upon the nature and severity of the infection, whether the treatment is curative or prophylactic, the age and condition of the recipient of the treatment and the method of administration and dosage regimen. Generally, however, a suitable response is observed with doses of from 5 to 200 mg./kg. of body weight. This of course must be adjusted to the individual case, utilizing sound professional judgement and careful observation of the response obtained.

As representative of the spectrum of antimicrobial activity for these compounds, the following minimum inhibitory concentrations may be noted:

I MINIMUM INHIBITORY CONCENTRATION (MIC) IN 'ylML. NUTRIENT MEDIUM The compounds of the present invention are administered parenterally or orally in any of the usual ,pharma: ceutical forms. These include solid and liquid oral unit dosage forms such as tablets, capsules, powders, suspensions, solutions, syrups and the like, including sustained release preparations, and fluid injectable forms such as sterile solutions and suspensions. The. term unit dosage .form as used in this specification and the claimsrefer to physically discrete units to be administered inisingle or multiple dosage to animals, each'unit containing 1a :pre' determined quantity of active material in association with the required diluent, carrier or vehicle. The quantity of active material is that calculated to produce the-desired therapeutic effect upon administration of'one or more of such units.

'Powders are prepared by comminuting the compound to a suitable fine size and mixing with a similarly com:- minuted diluent pharmaceutical carrier such as an edible carbohydrate material as for example,-starch. Sweetening, flavoring, preservative, dispersing and coloring agents can also be present. v I

Capsules are made by preparing a powder mixture as described above and filling formed gelatin sheaths. A lubricant such as talc, magnesium stearate and calcium stearate can be added to the powder mixture as an adjuvant before the filling operation; a glidant such as colloidal silica may be added to improve flow properties; a disintegrating or solubilizing agent may be added to improve the ava'i lability of the medicament when the capsule is ingested.

Tablets are made by preparing a powder mixture, granulating or slugging, adding a lubricant and disintegrant and pressing into tablets. A powder mixture is prepared by mixing the compound, suitably comminuted, with 'a. diluent or base such as starch, sucrose, kaolin, dicalcium phosphate and the like. The powder mixture canjbe granulated by wetting with a binder such as syrup, starch paste, acacia mucilage or solutions of cellulosic or polymeric materials and forcing through a screen. As an alternative to granulating, the powder mixture can be run through the tablet machine and the resulting imperfectly formed slugs broken into granules. The granules can be lubricated to prevent sticking to the tablet forming dies by means of the addition of stearic acid, a stearate salt, talc or mineral oil. The lubricated mixture is then compressed into tablets. The medicaments can also be combined with free flowing inert carriers and compressed into tablets directly without going through the granulating or slugging steps. A protective coating consisting of a vsealing coat of shellac, a coating of sugar or polymeric material and a polish coating of wax can be provided. Dyestufis can be added to these coatings to distinguish different unit dosages.

Oral fluids such as syrups and elixirs can be prepared in unit dosage form so that a given quantity, e.g.,-a teaspoonful, contains a predetermined amount of the-compound. Syrups can be prepared by dissolving the compound in a suitably flavored aqueous sucrose solution while elixirs are prepared through the use of a non-toxic alcoholic vehicle. Suspensions can be'formulated by dis- Strepto- Staphylo- Escherichia Pseudo'momas coccus census 7 coli ueruginoaa Proteus Klebsiella Aeromonaa Com ound from Example mega aureus vuliquenum er ms W Flensungen N 14 A 261 Bonn N 1 qtm's K10 8085 faciena Cloat- Clostridiu'm Alkali- Pasteu- Bordetella Mycoplasmae Mycoplasmae Mycoplasmae Compound from Example ridiu'm botugenes rella bronchiaallieepbovirhine gram!- number tetam' linum faecalis multocida septico ticum MS S6 lamm bhz l v ic hich in a vial and the vial and its'contents are sterilized and sealed. An accompanying vial or vehicle can be provided for mixing prior to administration.

In addition to their therapeutic use, the new compounds can also be used to promote the growth and improve feed utilization in animals, especially in raising young animals and fat-stock animals, as for example, calves, piglets and chicks.

The compoundsgcan be administered in the feedstufl, in special feedstuff -'preparations,in preparations containing vitamins and/or mineral salts, or in the drinking water. Such administration of the compounds permits prevention or treat'mentof infections caused by Gram negative and by Gram positive, bacteria-and by mycoplasma, and additionally 'c'ontribute's ma more rapid growth of the animals and to better feed efiiciency. In this embodiment, the compounds are preferably mixed into the feedstuif or the drinking water in a'concentration of 1 to 100 p.p.m.

The following examples will serve to further typify aitisg the nature of the present invention without being a limitation on the scope thereof:

EXAMPLE 1 H3O CH: g /N\I J 24.7 g. (0.1 mol) of 3-aminoquinoxaline-1,4-dioxide-2- dimethylamidine (Formula II, R R =methyl) are suspended in 125 ml. of benzene and treated with gaseous hydrogen chloride until saturation is reached. Thereafter phosgene is passed into the suspension at 80 C. for 2 hours. The resulting yellow intermediate product is filtered off, suspended in 150 ml. of ethanol and treated with 10 g. of triethylarnine. This results in a red-violet solution, from which red crystals of 1,2-dihydro-2-oxo-4- dimethylaminopyrimido [4,5 b] quinoxaline-5,10-dioxide separate after some time. Yield: 26 g. (95%), melting point: 227' C.

Analysis.--C H N O (273): Calculated: C, 52.7%; H, 4.0%; N, 25.3%. Found: C, 52.4%; H, 4.5%; N,

EXAMPLE 2 N NJ=O t n 0 14.3 g. (0.05 mol) of Z-piperidinocarbimido-B-aminoquinoxaline-l,4-dioxide in 150 ml. of chlorobenzene, are stirred with 6.5 g. of chloroformic acid methyl ester for 8 hours at 80 C. Thereafter the resulting intermediate product is filtered 01f and dissolved in dilute sodium hydroxide solution. 0n acidification with acetic acid, 9 g. (58% of theory) of 1,Z-dihydro-2-oxo-4-piperidino- -"...I r T 3:

Similar results are obtained, through equivalent amount of ethyl chloroformate 'EXAMPLES.3- -6' v u Utilizing equivalent: amounts :of i aminotiuinoxaline 1,4-dioxide-2-diethylamidine; 2 pyrrolidinocarbimido-iir aminoquinoxaline-1,4-dioxide; 2-morpholinocarbimido-3- aminoquinoxaline-1,4-dioxide and 2-hexamethyleneiminocarbimido-3-aminoquinoxaline-l,4-dioxide, respectively, the following compounds are obtained:

FormulaI M.P., Yield, Example number R Color degree percent 3 CnHs R d- 1 188-89 83 brown. N\ 02H: I

4 N/ --.-.do. l 188 B8 5 m ...do. 193-95 71 6 i Red 184-85 1 Decomposition.

What is claimed is:

1. A compound selected from the group consisting of a 1,2-dihydro-2-oxo-4-aminopyrimido [4,5-b]quinoxaline- 5,10-dioxide of the formula:

wherein each of R and R independent of the other is lower alkyl of 1 to 6 carbon atoms or (lower alkoxy) lower alkyl in which lower alkyl contains 1 to 6 carbon atoms and lower alkoxy contains 1 to 6 carbon atoms or R and R together with the nitrogen atom to which they are attached are pyrrolidino, piperidino, hexamethyleneimino or morpholino; and a pharmaceutically acceptable acid addition salt thereof.

2. A compoupnd according to claim 1 wherein R and R are each lower alkyl.

3. A compound according to claim 1 wherein R and R together with the nitrogen atom to which they are attached are pyrrolidino, piperidino, hexamethyleneimino or morpholino.

4. The compound according to claim 1 which is 1,2- dihydro-Z-oxo-4-dimethylaminopyrimido[4,5-b] quinoxaline-5,10-dioxide.

5. The compound according to claim 1 which is 1,2- dihydro-2-oxo 4 diethylaminopyrimido[4,5-b1quinoxaline-5,10-dioxide.

6. The compound according to claim 1 which is 1,2- dihydro 2 oxo-4-piperidinopyrimido[4,5-b]quinoxaline- 5,10-dioxide.

line-5'glo dioxidei inaenamopynmgaorgs-w quinoxaline-SJO-droxrde'. a

10. The process fori'thespreparation of a compound se- 1 ct dfrom.the, gr oup consisting of a 1,2-dihydro 2-ox0- wherein each of R and R independent of the other is lower alkyl of l to 6 carbon atoms or (lower alkoxy) lower alkyl in which lower alkyl contains 1 to 6 carbon atoms and lower alkoxy! contains lrto r6 carbon atoms or R and R together with the nitrogen atom to which t.hey areattached are pyrrolidino, piperidino, hexamethyl- 30 K8 eneimino or morpholino; and a pharmaceutically acceptreatfi antacid addition s'alfthereoffivliih' conip whereinR} and ,R? are sig ene or. lower alkyl chloroformat temperature offs fto m, about 20 to about 100 inu an' lertiorganiclsolvent and treating t m v iithq l fa ms with o ganic a'r'nine or inorganic base selected'froin the group.

consisting of a hydroxide, tcarbonate an d bicarbonateof an alkali metal or alkaline eartl rrn a1 Referenceslbrt UNITED STATES PAT N .,3,214,42s 1'0/1965; Ro /2 feg gilg; NICHOLAS s. mzzo; a s Examiner R. v. RUSH, Assistant Banner;

- -U.S-. c1. x.r;,,,. 250- 250 R, 251.5; 424-248, 

